1. Field of the Invention
The present invention relates to an imaging processing apparatus and a method of imaging processing.
2. Description of the Related Art
Imaging apparatuses perform imaging in a constant imaging period conforming to a video standard such as the NTSC system and the PAL system. NTSC is the abbreviation of “National Television System Committee.” PAL is the abbreviation of “Phase Alternating Line.” Specifically, an imaging apparatus conforming to the NTSC system performs imaging in an imaging period of 1/60 second (although an imaging period of 1/59.94 second correctly, it is written as an imaging period of 1/60 second in this specification). An imaging apparatus conforming to the PAL system performs imaging in an imaging period of 1/50 second.
In recent years, with the prevalence of light-emitting diodes (LEDs), light sources of various kinds of display devices have changed from light bulbs to LEDs. As to signals, light-bulb signals have progressively been replaced by LED signals, for example. LED signals look as if they keep lighting to human eyes. However, LED signals are driven by alternating current power supplies (AC power supplies). Consequently, LED signals actually repeat fast blinking in a constant blinking period, although it is difficult for human eyes to perceive that. Conventional technologies are described in Japanese Patent Application Laid-open No. 2009-17293 and Japanese Patent Application Laid-open No. 2010-93601, for example.
When an LED signal that repeats blinking in such a constant blinking period is imaged by an imaging apparatus conforming to the video standard such as the NTSC system or the PAL system, exposure may occur during an unlit period of a blinking period of the LED signal depending on a shutter speed. In this case, even though the LED signal is actually lit, the LED signal on a taken image is in an unlit state.
In order to solve this problem, a technique is developed that images LED signals by exposure with an imaging period other than the video standard such as the NTSC system or the PAL system. This technique performs exposure with an imaging period other than the video standard, whereby it is difficult to output image signals conforming to the video standard such as the NTSC system or the PAL system. Consequently, the technique is far from being able to solve the above problem as an imaging apparatus.
Another technique is developed that performs imaging by combining exposures with different imaging periods to increase probability of exposuring of an LED signal in a lit state. However, this technique has a problem in that exposure timing is made irregular, whereby it is difficult to maintain the continuity of an image, leading to inability to obtain an image in which the movement of a moving body is smooth. In other words, the technique has a problem in that the movement of a moving body is discontinuous and the movement of the moving body is awkward.